Prior art bearings have attempted to provide an environment with decreased friction. Unfortunately, such attempts have failed in that they have a shortened service life, thereby having excess maintenance requirements and short bearing reliability. U.S. Pat. No. 3,932,008, by McCloskey and Williams, describes a spherical bearing including a bearing liner having a low friction layer containing a resin matrix which includes therein a dispersion of self-lubricating particles including powdered or flock polytetrafluoroethylene (PTFE) particles and graphite fibers.
Self-lubricated bearings using PTFE as a sliding surface have been in use in the aerospace industry since the 1960's according to U.S. Pat. No. 4,666,318, assigned to Ampep, pic. Thin films of woven PTFE bearing surfaces are frequently reinforced with sintered bronze and textile yarns such as glass, graphite fibers, or high strength organic yarns of relatively high melting point. Woven structures are usually infused with resin systems such as phenol formaldehyde, epoxies or cyanoacrylates to bind the sliding surface into a dense structure. The inventors go on to teach improved bearings using a reinforced low-friction plastic element containing PTFE having a sliding surface and a counter face with a low surface roughness and high hardness.
U.S. Pat. No. 6,180,574 assigned to Rexnord Corporation describes a self-lubricating liner for bearings which includes a curable acrylate composition and a solid lubricant such as PTFE.
The abovementioned bearings, and other prior art bearings, have limited life. The prior art teaches bearings with self-lubricating liners containing fluoropolymer solid lubricants. New self-lubricated bearings are needed with improved service life to reduce maintenance requirements and cost as well as to increase the long term bearing reliability.